Indicating device for well drills



Nov. 3, 1942. A. D. WHITMAN 2,300,823

INDICATING DEVICE FOR WELL DRILLS Filed Dec. 18, 1959 2 Sheets-Sheet l Alvin D. Whitman INVENTOR.

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A TTORNEYS NOV. 3, 1942. D WHITMAN 2,300,823

INDICATING DEVICE FOR WELL DRILLS Filed Dec. 18, 1939 2 Sheets-Sheet? 5 /\/v/'n D. Whit man ATTORNEYS.

Patented Nov. 3, i942 twice WDIOATING DEVICE MB, i

Alvin D. Whitman, Houston, ien.

Application December 18, M39, deriai No. 309,795

ill Claims.

This invention relates to devices for indicating the nature of formations encountered by the drill in the process of well drilling.

In the drilling of deep wells it is desirable to provide means in connection with the drill which will indicate the nature oi the formation which is being drilled and particularly those containing oil or indications of the proximity to oil. The common method of determining the character of the formation is to employ a core drill which may be lowered down through the drill stem and the drill bit and employed to take a sample of the formation, which sample is withdrawn to the surface for examination. Such a method is time consuming and expensive and it is an object oi! this invention to provide means employed in connection with the well drill which will indicate the nature of the formations encountered in the well without the necessity oi withdrawing the drill for examination of the sample.

It is affurther object of the invention to provide a device which may be employed in combination with the well drill which may be lowered into position through the well drill and employed during the continuous operation of drilling to furnish an indication to the driller oi the presence of oil or gas in the hole.

The invention preferably employs an electrically actuated device for altering the passage for fluid circulation through the drill stem in response to the encounter, or penetration, of certain types of formations inthe lower end of the hole.

The invention will be better understood from a consideration oi an illustrative embodiment in the drawings accompanying this specification and wherein:

Fig. l is a central longitudinal section through the upper portion of the mechanism embodying the invention;

Fig; 2 is a similar view showing the lower end of the drill bit and signaling. mechanism;

Fig. 3 is a transverse section on the plane Fin 4 is a. central longitudinal section thru 'a modified form of the invention, portions of in drilling the well. It will be understood that as the particular construction of the drill l is not important. The upper end of the drill is provided with a shank 2 which is threaded on the interior to engage with a drill collar 3. The upper end of the drill collar may be connected with a drill stem t of the usual construction.

The drill bit itself is termed with an axial passage longitudinally thereof at a oi the proper size to receive therein a mandrel Said mandrel has a pin member i at its lower end threaded to engage with a sub t of some insulating material such as Bakelite. The lower end of the sub is threaded to engage with the shank Q of a pilot bit it. In the outer periphery of the suh 8 is a collar H, which is fitted within a circumierential. recess in the periphery oi the insulatins sub.

Adjacent the upper end of the mandrel ii the outer diameteris increased somewhat to provide a shoulder at it which may engage with a stop shoulder it in the head of the .bit. The mandrel is provided with a longitudinal passage it for the fluid circulation. This passage is connected for discharge at the lower end with openings to in the opposite faces of the pilot bit ill. at the upper end of the mandrel the passace ill diverges at it to connect with the space it within the drill collar.

The space It accommodates the downward circulation through the drill stem of the flushing fluid for the main drill bit i. It connects at the upper end of the drill with passages ii and it, which carry the fluid onto the bottom of the hole in front of the advancinu faces of the drill.

Above the mandrel is a housing it, which is screwed over the upper end of the mandrel to thereby close the lower end of the housing. the upper end of the housing heins; closed by a plug: 26, which serves as a mounting tor the latch housing ii. It will be noted that the housin it has a chamber it therein which is closed against the access of liquid to the interior during the operation of the tool. The housing has therein an electromagnet it, the core to. of which cooperates with the switch arm iii. The coil 23 of the electromagnet is connected with a hattery Or other source of electricity it. The electric circuit including the coil and the battery also includes wires which are extcndm from the chamber downwardly, through an'openinp indicated at ii, connection at its lower end with the sub if. The passage allows the connection of one of the wires of the circuit with the collar it of conducting material. The other wire of Thus, a small current will normally pass through the coil of the magnet so that the energizing of the magnet will hold the switch arm 25 away from two terminals 28 and 29 or the second electric circuit.

The arm 25 in this embodiment i normally urged into position to close the circuit through the two terminals 28 and 29 by a spring 30. The circuit including the terminals 28 and 29 has therein a battery 3! and the wires leading from these terminals extend outwardly through the wall of the housing and are extended upwardly through a latch collar 32 and into a chamber 33 in the latch stem 34.

The latch stem 34 has its lower end slidable within the latch housing 21! and has at its lower end a tran verse pin 35 which engages witlmi a slot 38 of a. latch'arm 31 pivoted at 3B in the lower end of the housing 2!. The upper end of the, latch dog 31, is adapted to engage below the ring'32 when the pin 35 is in its lower positions It will be obvious that when the latch stem 34 is moved upwardly the movement of the pin 35 in the slot 38 will unlatch the dog. There is a radial flange 39 on the latch stem which is adapted 'to engage the upper end of the housing 2! to limit the downward movement of the stem.

The chamber 33 within the latch stem is adapted to be filled with explosives and the circuit 40 which includes the terminals 28, and 23 is extended into the latch stem and has in the circuit on igniting element ii which, when energized, will act to explode the charge of powder within the chamber 33 and force a plug d2 laterally from an opening in the chamber which is normally closed by said plug.

The plug 42 serves as a stop for a valve member 43 slidable upon the latch stem and limited in. its upward movement by a collar dd on the stem. When the plug as is removed from below the valve said valve willvdrop and engage within .a. seat 65 within a ring dfiiixedupon the interior of the drill stem to closethe'drill pipe and signal the driller by the resultantj'increase in pressure.

In the modified tor-moi, the invention as shown in Figs. 4, and 6, the mahdrei; 8 and the pilot bit is are made unitary. Inthis embodiment a minute current normally passes thru the electromagnet 28 for reasons that will be more fully apparent. and current is insuficient to magnetize the core 2% sumciently that the arm 25 will be drawn downwardly against the tension of the spring 36. The arm 25 is therefore normally held upwardly away from terminals which in this embodiment are placed below the normal position of the arm 25. In this manner thecircuit from the battery 29 thru the conductors 43 to the ignition element ti will normally remain open as in the previously described embodiment.

It is known that certain frequencies of a limited range are set up in a drill bit and stem when the bit is operating within a stratum having particular characteristics. In order to take advantage of this fact a vibration responsive element BI is mounted within a chamber 58 in the pilot bit Iii. The element M is so constructed that ascaeee electromagnet 23 a above indicated. The element 5| is, however, responsive toa predetermined band of frequencies to permit a greater current to pass therethru. such current being sufficient to pull the arm 25 downwardly whereby the circuit thru the ignition element 4| is closed whereby desired indications are produced.

In Fig. 6 there is shown a further modification in which the member 43' corresponds to the valve member 43 in Fig. 1. This member is smaller than the internal diameter of the ring 46' fixed in position within the drill stem 4. There is therefore normally a throttling of the fluid between the elements 43' and 46'. If, however, the electromagnet 23 is deenergized and the plug 42 is forced from its normal position, the member 43' will move downwardly upon the latch stem 34 and the throttling action upon the pumped drilling fluid will be immediately decreased. Again the change in pumping conditions indicates that the plug 42 has been removed, such condition also indicating that the pilot bit has entered into a stratum of predetermined character.

In the operation of the device of the invention the pflotbittoget-her with the housing is, latching device 31 and valve member 43 are lowered downwardly through the drill bit. When the device is thus seated the valve 43 will beheld in a fixed position relative to the valve seat by the plug 42. In the normal operation of the drill the pilot bit will be rotated by means of the main drill through connection of any preferred form between the two members and preferably from the mandrel adjacent the shoulder I2 at the point 41 of polygonal shape so that the two'parts will be held against relative rotation.

The latch 31 engaging below the ring 32 will permit the exertion of a downward thrust upon the pilot bit as the drill is operated. If a formation of relatively high electrical resistance such as one containing oil or gas is encountered in the hole when using the embodiment shown in Figs.

only a minute current normally flows thru the increased the pull of the electromagnet 1 2 will be sufiicien .y changed that the 2! will m drawn downwardly to close the circuit across the two terminals 23 and 23. when this isfdone the current will flow through the circuit 43 heating up the igniter element 4i and by the firing of the explosive within the latching stem the plug 42 will be removed from its position and the downward circulation of the flushing fluid will mm the valve 43 downwardly and thus alter the circulation of fluid from the pumps. This indicate at once to the operator that a seems-mi formation has been encountered. It will then be possible for the operator to lower an overshot engaging over the upper end 43 of the latch A pull may then be exerted on the latch stem to withdraw the latch 31 and allow' the tool to be withdrawn from the well. A well tester or. other sampling device may then be lowered through the drill stem so as to obtain an accurate sample of the fluid and formation at the bottom of the well.

accuses It will be obvious that when the device of the invention is used the rimning of a well tester or sample taking bit frequently into the well will be avoided. The device may beemployed during the ordinary drilling and "will tend to inform the driller when itis desirable-"to makes. of the formation. The advantages oi this structure will be obvious to those skilled in the art.

What is claimed is:' 1. A drill stem, a well drill thereon having an axial passage, an upwardly presented shoulder in circuit with said source, an electrode in saidcircuit connected with the outside of said insulating sub,- another electrode on said drill, there being drilling fluid in the well outside said drill stem whereby an electric current is conducted between said electrodes through the adjacent formation, a magnet in said circuit normally energized by said battery and said electrolyte, a second circuit, a switch in said second circuit normally urged to closed position by a spring, but positioned to be held open by said magnet. a latch stem to opera o said latch, a valve on said stem, 9. seat therefor in said drill stem, a chamber for explosives in said stem, a plug closing said chamber and also acting to hold said valve from its seat, an igniting element in said chamber connected in said second circuit to explode the charge in said chamber when said second circuit is closed by said switch and thus remove'said plug and release said valve to alter the passage through said drill stem.

2. A well drill, a drill stem connected therewith, a mandrel supported for rotation with said drill, a pilot bit on said mandrel, a battery housed in said mandrel, wires in circuit with said battery and having spaced terminals insulated from each other at the lower end of said mandrel, a chamber for explosives above said mandrel, a plug closing one side of said chamber, a valve supported on said plug, a seat for said valve in said drill stem below said valve, a normally energized electro-magnet in said circuit, and means actuated in response to the deenergizing oi said magnet to displace said plug and allow said valve to move toward said seat.

3, A well drill, a drill stem connected there- 'with, a mandrel, a pilot drill on said mandrel projecting below said drill, means to insulate said pilot drill from said mandrel, a battery housed in said mandrel, wires connected in circuit with said battery and having spaced terminals on said pilot drill and said insulating means, the flushing fluid between said terminals forming an electrolyte, a valve seat insaid drill stem above said mandrel, a valve, means supporting said valve above said seat, and means responsive to the breaking of said circuit to release said support and allow said valve to seat and close oil! the I passage of fluid.

said mandrel, a valve, means supporting said valve above said seat, a charge of explosives behind said support, an electric igniter in said charge, a second electric circuit including said igniter, and means responsive to the breaking of said first named circuit to close said second circuit to explode said charge to release said support and allow said valve to move to restrict the passage or fluid.

5. In a device of the character described, a drill stem, a drill thereon, a mandrel supported axially of said drill, a pilot drill on said mandrel, an electric circuit including an electromagnet, terminals in said circuit insulated from each other at the low r end of said mandrel, flushing fluid about said drill stem and drill adapted to conduct an electric current between said terminals through the surrounding formation and to normally maintain said electromagnet energized, and signalling means operating in response to the interrupting or current through said circuit and the deenergizing 01' said electromagnet when a formation of high electrical resistance is encountered.

6. In a device of the character described, a drill stem, a drill thereon, a mandrel supported axially of said drill, a pilot drill on said mandrel,

an electric circuit, terminals in said circuit insulated from each other at the lower end of said mandrel, flushing fluid about said drill stem and drill adapted to conduct an electric current from the terminal to the surrounding formation, an electromagnet in said circuit ordinarily energized when said electrolyte and aconductive formation are present, but deenergized when an insulating formation reduces the flow of electricity between said terminals, a valve in said drillstem above said mandrel, a seat therefor, means to support said valve above said seat, said supporting means being rendered ineffective to support said valve in response to the reduction of current in said circuit.

7. In a device oi the character described the combination oi, a well drill, a drill stem connected thereto, a pilot bit removably mounted in said drill and adapted to rotate therewith, said drill stem providing a passage for drilling fluid downwardly to the well drill, a valve seat in said stem, a valve, means supporting said valve adjacent the seat, and means responsive to the pence tration of a formation of predetermined nature for releasing the valve for movement relative to the seat, whereby a signal is transmitted to the surface through the fluid in the drill stem.

8. In a device of the character described the combination of, a well drill, a drill stem connected thereto and providing a passage for drilling fluid downwardly to the well drill, a valve seat in said stem, a valve, means supporting said valve in spaced relation with saidv seat, and means responsive to the penetration of a formation of predetermined nature for releasing said valve for movement relative to said seat, whereby a signal is transmitted to the surface through the fluid in the drill stem.

9. A device for signalling the surface that a formation having predetermined characteristics has been penetrated during the drilling operation including means to pump a drilling fluid downwardly through a drill string during the drilling operation, means carried by the drill string to apply a difierence in potential to spaced terminals on the exterior of the'device during drilling, and means for automatically varying the rate of flow of the drilling fluid when the resistivity conductivity of the formation being penetrated by the drilling changes sufllciently to afiect the potential between the terminals 10. A device for signalling the surface that a formation having predetermined characteristics has been penetrated during the drilling operation including means to pump a drilling fluid downwardly through a drill string during the drilling operation, means carried by the drill string to apply a difference in potential to spaced termlpals on the exterior of the device during drilllag, and means for automatically varying the rate of how of th drilling fluid when the resistivity conductivity of the formation being penetrated bythe drilling changes sufliciently to aflect the potential between the terminals so that the variation in floww caused by said last means will heeflectiveat the surface.

" ALVIN D. WHITMAN. 

